Chemical concentration of ore values.



C. S. BRADLEY.

CHEMICAL coNcENTRATroN 0F ORE VALUES.

APPLICATION FILED MAR. l0, 1913.

Ore

Mihai Patented Nov. 14, 1916. A

UNITED sTATEs PATENT oEEioE.

CHARLES` S. BRADLEY, 0F NE'W YORK, N. Y.

OHEMICAL CONCENTRATION OF ORE VALUES.

Specification of Letters Patent.

Application led March 10, 1913. Serial N o. 753,287.

To all whom t may concern.'

Be it known that I, CHARLES S. BRADLEY, a citizen of the United States, residing in the city, county, and State of New York, have invented certain new 'and useful Improvements in Chemical Concentration of Ore Values, of Which the following is a full and clear specification.

The present invention relates to the concentration or recovery of ore values by wet chemical methods.

The invention comprises an improved method of conducting the operations of chemical concentration, apart from the specific materials or chemical vreactions employed; and the inventionfurther comprises a number of improved chemical treatments which are of especial importance in the concentration of ore values.

-According to my presentinvention, I conduct the operations in such manner that the necessity for chemical analysis is largely` avoided and excesses of the -reagents employed may be maintained without loss, whereby complete .extraction is obtained, the operations proceed with a minimum of attention, and the supply of acid radical and oxygen may be readily' andpositively ad-v )usted Where metals of variable valency are to be recovered, the presence of high valency compounds is highly advantageous to the extraction as they aid in the dissolving of the values and tend toward complete extraction. On the other hand, the separation of the values from the solution, and their ultimate recovery in highly concentrated form may be more economically effected from the low valency compounds, as these are already partiallyY reduced, Thesek considerations lead me to proceed with a view to the recovery of thevalues from the low valency compounds, and to throw back to the extraction apparatus the high valency compounds to aid oxidation. The presence of acid radical'is necessary to the dissolving of ore values, andsulfurous and sulfuric are the ones 'usually available.Y Hydro,- chloric acid radicaly can berk made available through the provision of 'a chlorid carrier solution such'as calcium chlorid, the action of the sulfuric acid upon this-being to produce hydrochloric acid and insoluble calcium sulfate. In order to prevent the escape of acid fumes into the atmosphere, and to render a portion of the highvalency compounds available for the dissolving of values, I conduct the throw back operation so as to subject the excess acid fumes to the high. valency compounds, as I have found that the high valency compounds absorb acid fumes with great avidity.

The throw back, or arrest and return of part of the values to a preceding step or position in the system, is one of the important features of my' invention, not only for the` reasons already apparent, but also in the pai-tation or selective recoveryV of the ore values. Not only do the high valency compounds provide solvents, but they reject from solution those substances having less avidity for the acid radical employed. This rejection of the values of less avidity for the acid radical may be vutilized as a means of their recovery or it may serve to eliminate undesired metals not,\vo1th recovering, Whose presence in the solution would reduce the capacity of the solution for dissolving those values sought to -be recovered. Where metals of variable valency are concerned this principle of operat1on may be intimately connected with the variations of the properties of the salts or compounds of the metalat different valencies and advantage can be taken of these conditions. The two oxidsof copper, in connection with calcium chlorid dissolving and carrier solution, will serve as an example. There is a wide difference between 'the avidity of the two oxids of copper for Patented Nov. 14,1916. r

hydrochloric acidv in the presence of an ex'- v cess solution of many chlorids, such as calcium chlorid and sodium chlorid. Indeed so great is this difference in the case of the two copper oxids that zinc oxid or calcium carbonate will precipitate cupric compounds from chlorid solutions whereas cuprous chlorid would not be affected. On the other hand, cuprous oXid precipitates zinc compounds from chlorid of zinc solutions. Cupric compounds have greater avidity for chlorid solutions than iron and aluminum, and hence the latter are precipita-ted by the former. Calcium oxid for example will precipitate iron, aluminum, copper and zinc oxids from vchlorid solutions. It is thus apparent that in the case of a mixed ore containing for example iron, aluminum, copper and zinc for which chlorid solutions are employed, the throw back principle` could, if desired, be carried out by yprecipilooV -oxid and last of all precipitating iron and aluminum by throwing back cupric compounds. In this way, the solutions could first be freed from iron and laluminum by utilizing the cupric compounds, next. be freed of ycupric compounds by throwing back the zinc and be fieed of zinc by throwing back cuprous oxid and finally freed of cuprous compounds by introducing calcium oxid. lVhile the present invention is not to be yunderstood as necessarily utilizing the thrdw back principle to this extent, the *above example will, nevertheless, illustrate clearly the principle involved and is to be understood as coming within the broad scope of the invention.

To illustrate clearly the facility of commercial operation under the principles of my present invention I may refer to an embodiment of the invention in the chemical concentration of copper values from mixed oresI containing iron and aluminum which it is 'desired to eliminate. It is to be understood, however, that the principles of the invention could be applied to the recovery of iron, aluminumor any of the othermetals if desired, and the invention is not to be understood as being limited to the particular embodiment to which I referV for illustration.

In my prior Patent No. 1,011,562, granted I, Y December 1Q, 1911, I have shown and described a method in which the ore is first amphidized to Arender the "allies soluble, mainly as sulfates, the amphidized ore is then subjected/to the action of a calcium chlorid dissolving land carrier solution maintained in excess of that required to dissolve the values, whereby-the sulfates are converted into chlorids and the sulfate radical combined with calcium to f orm insoluble calcium sulfate,` the solution containing the ore values in' the form of chlorids is next freed of thev gangue material and the precipitated waste products vby filtration, and the 'values ultimately recovered from the dissolving and' carrier solution of calcium chlorid by means of calcium carbonate, for example, which regenerates the calcium chloridsolution for re-use in the system. 1 shall assume that it was desired in a sys tem of that general nature to keep the iron and-aluminuml out of the solution from which the copper is to be recovered, and that there is an excess of free acid to be absorbed. In describing the method employed, reference is made lto the accompanying drawing.

The drawing shows diagrammaticallv a system for obtaining the values in solution.

The finely divided ore or other substance bearing values, hereinafter referred to as ore, is subjected to the amphidizing operation in the amphidizer 1, from which the volatile' products comprising the dust and fumes pass into the dust and fumes absorbing drum 2. The absorption of the dust and fumes will be better understood after description of the other features of the method upon which it depends, and hence will be referred to more in detail hereinafter. The amphidized ore from the amphidizer 1 and the products from the dust and fumes drum 2 are introduced into the solution drum 3 where the sulfates are converted into chlorids by the action of a calcium chlorid dissolving and carrier solution which is maintained .in considerable excess of that required for dissolving the values. As a result of this action the values will be in the form of cupric and cuprous chlorids, iron and aluminum chlorids, and zinc chlorid, disregarding for the present the rejection of the iron and aluminum which will be explained later in more detail. The entire mass of solutions and gangue material is then delivered to the filters 4, by which the solutions containing the values are separated from the gangue material. The gangue material is discharged from the system as indicated by the arrow 5, and the clear solutions comprisingl the calcium chlorid carrier and cuprous chlorid, cupric chlorid, iron and aluminum chlorids, and zinc chlorid, are introduced into the high valency precipitation drum to which is delivered a precipitating agent such as for example calcium carbonate, whereby the high valency copper compounds are precipitated. Iron and aluminum chlorids cannot remain in solution in the presence of insoluble copper, as the latter would replace the former as fast as formed, and consequently the precipitation of 4all the cupric copper insures the vcomplete rejection of all the iron and aluminum from the solution. The cuprous copper and the zinc chlorid, on the other hand are not acted upon by the calcium carbonate, and consequently the calcium carbonate may be introduced in excess without the necessity of prior analysis of the solutions for quantitative determinations.

The solutions and precipitate are then disv A lency copper compounds a'ndiron and aluv mmum.

Any excess calcium carbonate will be mixed in with the high valencv precipitates. L In the4 example of the high valency precipitation herein given, the calcium carbonate regenerates the calcium chlorid solution, thus avoiding loss of chlorin and providing for the formation of an insoluble sulfate .from the sulfuric radical after the latter has completed its function of makingthe values amenable to the dissolving action of the calcium chlorid solution in the exe traction operation. Itis to be understood, however, that the regeneration of the carrier solution at this or anv other particular place in the concentrating method is not a neces sary consideration to the operation of the particular improvement which the present invention contemplates, and therefore the high valencv precipitation may be performed with any other suitable reagent without departing from the spirit and principles ot' my present invention, and the regeneration of the carrier solution may be accomplished if desired at some other point in the system. i The separation of the 10W valency compounds from the high valency compounds. so that the recovery may be made from the former and the. extraction aided b v the latter, is however a feature of the present embodiment of the invention, and therefore the invention contemplates the use of a reagent which will selectively precipitate. for example, the high valency copper while leaving the low valency copper in solution, at this point in the method.

Returning again to a consideration of the low valency solution and the high valency precipitates, the solutions are treated in any suitable manner to effect the recovery of their values. preferably "in some Way as b v calcium oxid that leaves the carrier solution in suitable form for return to the extraction operation. the return of calcium chlorid solution to the extraction apparatus, as, for example, by introducing it-into the 'dust and fumes drum 2. Any silver present in the ore will have been taken into the extraction solutions as silver chlorid, and as this substance is highly soluble in vthe cuprous chlorid and calcium chlorid solution, it will tend to o with the cuprous chlorid rather than precipitate with the high valency compounds. Therefore the silver ma)v be recovered from the solutions after the high valencvY compounds have been separated fromthe solutions and beforevthe low valency copper and the zinc have been recovered. 'l`he high valencv precipitates are in accordance with the present example of the `invention delivered into a bin 8 or other suitable receiver, from whichthe)1 are returned to the extraction apparatus and where they ma v increase or decrease in quantity according to the rate of supply from the preciliitating step referred to and the rate Kat which they are thrown back into I have, therefore, indicated the extraction apparatus, which will now be descr1bed.

The high valenc)v compounds can be recognized or distinguished from each other bv- This precipitate when pure, has a clear green color. The iron precipitate has a reddish or brownish color. When the copper precipitate has iron mixed with it. the clear green of the trioxychlorid is discolored by the reddish or brownish color, varying in degree with the proportion of iron present.. The color of the precipitate may be taken as an iudicationof the amount of iron` which is being taken into solution in the extraction step.' The presence of dissolved iron insures the complete extraction of the copper, as iron can not remain in the solution in the presence of undissolved copper.

'1`herefore it is not desirable to prevent entirel. v the presence of iron. for fear that some ofthe copper ma)v be left unextracted from the ore, and one of the important features of my invention is the maintenance of an indeterminate quantity of'a substance, such as iron, of less avidity than the values for the acid radical employed, so as to insure complete extraction. Excess acid. over land above that required for dissolving the copper and Zinc. will tend to bring iron and aluminum into solution, and therefore the discoloration of the precipitate likewise indicates the excess of acid bevond that required for dissolving the copper and zinc. Bv throwing back the precipitated high valenc'v, compounds, free acid maY be absorbed and iron and aluminum rejected from the solution. The readv adjustment of the quantity of the precipitate which it is desirable to thi-ow back, can therefore lbe obtained without predetermination of the quantities involved but entirely from the observation of the color of the precipitate` thus avoiding the necessity of chemical analysis. lreferablvv the quantity is so adjusted as to keepthe precipitate slightly tinged with the iron color, as the complete extraction of the copper is thereinv insured. The particular method of conductingr the ore concentrating method according to 'the present example of my invention.4 vthat is to sav, the separation of the low valencv compounds for the recoverv of values` and the arrest -and return or throwing back of the high valenc.)1 compounds, enables the mailitcnance of iron in the extraction solutionsto serve as a margin of safety to prevent loss of copper, to avoid chemical analysis, and

BEST AvAiLABLE coP in :ilisorl'iingltliv fivv acid may heindicated as follows:

lt will hv'ohserved from these equations, that the action of thv high valvncy precipitatv upon thv trvv acid produces further quantities of lowvi valvnt' vomiioundsv for the'suhsequvnt rvvovvrv operations;

When thv supply of high valviicv precipitatvs is insiillivivnt for the complete absorption ol" tliv excess frvv acid.` thv supply of calcium vai'honatv lor the like may be increased. which will svrvv to further absorb thv-free acid. as thv excess calcium arhonl ate is carried with thv high valviivy precipi-y ltate to thv avid.absorption apparatus` where it will pi'oduvv further quantities of trioxichlorid to siipplvinviit the amount thrown back. yl`liv color of thv high valencyprvcipitate will in this vasv he a guide. to the read)v adjustment of thv supplv ol calviuin carbonate to thv high valviivv precipitation.

When tliifsiiiiiily ot' avid is insullicivnt. the' ouantitiol the high valvnc'v precipitate in thv hin will increase. 'l`liv sulfur content of the orv ma)A thvn hv inci'vasvd.` :is this will have thv ell'evt ol' prvaluving more acid.

If the uuantit)v of precipitate returned is' adjusted so as to keep thv precipitate a unil form color. thv uuantitiv ol' precipitate in thv hin will hv an indication ol thv proper sillfur content of thv ore. as it'` thv sulfur contviit is high. thv precipitate will decrease` and if lowlwill increase.

lt is obvious` that trvv avid fumes may, if desired. he removed lroin thv svsteniwithoutsuhjvvting tliviii to absorption` for use in any other desired opvi'ation. and also that whvrv thv quantity ot' triox'vehlorid runs in excess of that required in the system, part ofl it may hv ivniovvd and treated for recovery.'

ll'hat l claim is:

l. The iiivtliod oll concentrating orc I values, which coiiiprisvs obtaining values in solution asy variahlv valentv compounds in thv. ons and iv condition. prvvil'iitating'and returning to thv extraction apparatus high valvncv compounds. and recovering thv values in thv l'orin ot- -low valent-y coinpounds.

Z. The invthod ot' concentrating ore values. which comprises obtaining values in solution as variahlv valvncy compounds in thel ous and ivivonditioii. selectively pre-A cipitating high valent-iY compounds andrevalues in so1ution,yand recoverin from the remaining solution the low vii ency comto an extraction operation for disso ving thc soluble constituent-s, selectively precipitat-v i ing and returning to the extraction operation a part of the dissolved constituents, and subjecting the remaining solution to a recover)v operation for the recovery of values` contained therein.

4. The method of concentrating ore values. which comprises dissolving silbstances of (litferent avidity for the acid radical employed. continuously kprecipitating and throwing hack to the extraction apparatus part of the substance for rejectin from solution substance of less avidity or the avid radical, and recovering substance of grvatvr avidit)Y from the remaining solution.

The method of concentrating ore values. which comprises dissolving values, continuously precipitating and throwing hack to the extraction apparatus part of the values to reject from solution substances of less avidity for the acid radical employed, alid recoveringvalues from thv remaining solution.

(. The nivtliod f of' .concentrating oi'e values` which comprises dissolving values,`

continuouslyI precipitating and .throwing hack in cyclic manner part of the values toy dissolve -further values. and recovering values from the remaining solution.

T. The method of concentrating ore values. wliivli comprises dissolving values. continuously precipitating and throwing hack incvclic manner to the extraction apr paratus part of the values to absorb excess free acid. and recovering values from vthe remaining solution. i

h'. The method -of` convent'ating ore values. which comprises taking into solu-` tion the values. together with a substance of less avidity for the acid radical employed, precipitating and throwing back to the extraction apparatus the substance of less avidity, and recovering values from the remaining solution. thus freed of the substance of less avidity.

Q "lhe method of concentrating ore values` which comprises taking into sollition the values. together with a substance of lvss avidity for the acid radical vinploycd, rviiioving ganguv material from the solu-` tions. precipitating the substance 'of less,

aviditv andthrowing it havlt in c vclic inannvr to a point in thv system preceding the rvnioval of gan'gue material. and recovering values from the. remaining solution thus freed of the substance of less avidity.

1t). The method of concvntrating orc values. which con'iprises taking into solution 5 turning them to the operation of obtainingv the values. together with v"u substance of less aviditv for the acid radical employed, 4,removing gangue material fromlthe'solutions,

precipitating and thrt'iiii'ngfback-to the ex-f maininr solution thus freed of the substance D of'less avidity. *j y j 11. The method `ot concentrating ore values, which compris taking into Vsoluftion the values comprising variable valency compounds in the ous and ic condition, together vwith a substance ot' less avidit)r for the acid radical employed. precipitating and throwing back tothe extraction apparatus the high valency values together with.y the substance of, less avidity,`r and recovering values from vthe remaining.'solution thus freed of the substance of less` avidity. l2. The method of conducting'the operations of chemicalconcentration 'of ore values, which comprises subjecting the ore containing variable valencv salts vin the ous and ic condition and other compounds of `metals to the action of a dissolvitigand carrier solution. removing the gangue material from the. resultingsolution of variable vale'ncv salts, precipitating high valencv compounds and throwing them .bac-k' in cyclic manner to a point in the system preceding the ie-:f inoval of gangue material. and recovering values from thel remaining solution.

13. The method of conducting the oper-L ations ot' chemical concentration of ore values. which comprises subjecting the ore containing variable valency salts in the ous and ic condition and other compounds of metals ygether with a substanceof less avidity for the acid radical emplo ved,throwing back` to the ls vsteni''more or less ot' thel precipitate according to the proportion ot the "substance ot' less aviditv present in the precipitate, and recovering valuesvt'roni the remaining solution. 5 14. The method ot conducting the operations of chemical concentration of ore values. which comprises subjecting the ore to an extraction operation 'wherebv is obtained a solution oi values and a .substance 'of less aviditv for the acidradical emploved'precipitating part ot' the vvalues 'together with the substance of less aviditv` and returning to the extraction operation more or lessot' the. precipitate as the quantitv of substance oi" less aviditv in the solution coming from the extraction operation increases or decreases.

l5. The ,method oi conducting"-the operationsoli'chemical concentration ore valu'cs, which comprises subjecting 'theor'e to an extraction operation whereby is obtained Va solution of ,valnesand"zi-substance of less ues. which comprises subjecting the ore conl taining an acid radical developed therein, to an extraction operation whereby is obtained a solution'otvalues and a substance of less 'avidityr for the acid radical, precipitating part otl the values together with the substance of less aviditv, utilizing the precipitate for absorbing excess freeacid, and reducing the supply of acid radical as the available suppl)7 of the precipitate diminishes.

17. The. method ot' conducting the operations of chemical concentration of oie values. which comprises taking values into s0- lution as variable valencv compounds, precipitating high valencv compounds and returning them vin c vclic manner to oxidize vthe substances subjected to the dissolving operation. adjusting the return of the high valency compounds to regulate the oxidation,`and recovering values from the remaining solution.

1S. The method of conducting thev operations of chemical concentration. ot' orel'fval-H employed. precipitating high valencyyalues together with the substance oi less a'viditv, utilizing the precipitate to oxidize the substancessubjected to the dissolving operation` and adjusting the quant-itv of the precipitate thus employed according to the quantity of the substance of less avidity therein. to regulate the oxidation.

19. The method of conducting the operations of chemical concentration of ore valjusting the .quantity ot' the"precipitate thuseinploved according to the discoloration, to regulate the oxidation. l

:20. rl`he method ot concentrating copper values. which comprises subjecting-the ore containingcopper. iron and aluminum to a dissolving f and carrier solution. removing gaiiguc material, precipitating high -valency .copper values together with the iron and dissolving and carrier solution, removing gangue material, precipitating high valency copper values, with the iron and aluminum contents, throwing back the preci itate to reject iron and aluminum from soyution in the dissolving operation, adjusting the quantity of the precipitate thrown back according to the color ofthe preci itate to regulate the quantity of iron and a uminum carried inthe solution coming from the diolving operation, and recovering copper values from the remaining low valency solution.

22. The method of concentrating copper values, which comprises subjecting the ore containing copper, iron and aluminum to an extraction operation, removi gangue material, precipitating high va ency copper values together with the iron and aluminum contents, utilizing the high valency precipitate for oxidation in the ,extraction o ration, adjusting the quantity of high va ency precipitate thus employed according to the iron color in the precipitate, to regulate the oxidation, and recovering values from the low valency solution.

23. The method of concentrating copper values, which comprises subjecting the ore containing copper, iron and aluminum to an extraction operation, removing gangue inaterial, precipitating high valency copper values together with the iron and aluminum contents, utilizing the precipitate to reject iron and aluminum in the extraction operation, adjusting the quantity of high valency precipitate thus employed according to the iron color in the precipitate to leave an indeterminate quantity of iron and aluminum in the solution coming from the extraction operation so as to insure complete extraction of thc copper without predeterinination of the quantities involved, and recovering copper values from the remaining low valency solution.

24. The method of concentrating copper values, which. comprises subjecting the ore containing copper, iron and aluminum, with an acid radical developed therefrom` to an extraction operation, removing gangue material, precipitating high valency copper values together with the iron and aluminum contents, utilizing the precipitate for labsorbing excess acid radical, adjusting the quantity of precipitate thus employed according to the iron color of the precipitate to regulate the quantity of free acid radical, and recovering copper values from the remaining low valency solution.

25. The method of concentrating ore values, which comprises amphidizing the ore, subjecting the amphidized ore to the action of a dissolving and carrier solution,

precipitating high valency values and utiizing the precipitate for absorbing excess acid fumes from the amphidizing treatment and for oxidizing the substances subjected tothe action of the dissolving and carrier solution, and recovering low valency values from the remaining solution.

26. The method of concentrating ore values, which comprises amphidizing the ore. subjectin, the amphidized ore to the action of a dissolving and carrier solution, precipitating high valency values and sub- ]ecting them to the action of excess acid fumes from the amphidizing treatment and to the action of the am hidized substance, whereby the excess acid iiimes are absorbed, the amphidized substances further oxidized and the high "alency precipitate reduced and redissolved, and recovering values from the remaining solution of low valency compounds.

27. The method of concentrating ore values, which comprises amphidizing the ore, dissolving from the am hidized yore the values together with a su nce yof less avidity for the acid radical employed, pre

cipitating part of the values together with the substance of less avidity and utilizing the precipitate to absorb excess acid fumes from the amphidizing treatment, adjusting the quantity of the precipitate thus employed according to the quantity of the substance of less avidity in the precipitate to regulate the absorption of acid fumes, and recovering values from the remaining solution.

28. The method of concentrating copper and zinc values, which comprises obtaining from the ore a solution of variable valency copper values and the zinc values, precipitating high valency copper values and throwing Vtbein back to the extraction apparatus to reject substances of less avidity for the acid radical employed, recovering the zinc values from the remaining values from the solution and then recovering the low valency copper values from the solution thus depleted of zinc.

29. The method of lconcentrating copper, zinc and silver values, which com rises obtaining from the ore a solution o variable valency copper values. the zinc values and the silver values, precipitating high valency copper values, recovering the silver values' from the remaining solution, then recovering the zinc "alues from the solution thus depleted of silver, and then recovering the low valency copper values from the solution thus depleted of zinc.

30. The method of concentrating copper, zincl and silver values, which com rises obtaimng from the ore a solution o variable ,valency copper values, the zinc values and thus depleted of silver, and the'n recovering the lsilver Values, precipitating high valency the low valency copper values from the solu- 10 copper values and throwing t'hem back to tion thus depleted of zinc.

the extraction apparats to reject from soluf CHARLES. S BRADLEY.

f tion substances of' less avidity for the afcid radical employed, recovering the silver Witnesses: Values from the remaining solutlon, then rev WM. A. COURTLAND, coverlng the zinc values from the solution OCTAVIUS KNIGHT. 

